Experimental evaluation of adaptive beamforming methods and interference models for high frequency over-the-horizon radar systems

Abstract

This paper experimentally evaluates the interference cancellation performance of different adaptive beamforming schemes applicable to high frequency (HF) over-the-horizon (OTH) radar systems. Such systems are known to receive multipath and diffusely scattered radio frequency interference produced as a result of reflection from the stratified, dynamic and spatially inhomogeneous ionospheric propagation medium. Apart from quantifying the effectiveness of operational adaptive beamformers in the HF (3–30 MHz) environment, realistic interference models are described and experimentally evaluated in terms of their ability to predict the observed interference cancellation performance which is not well represented by traditional models. Adaptive beamforming algorithms with robustness against jammer motion are also described and their effectiveness is experimentally demonstrated using interference data collected by 32 narrowband receivers of the very wide aperture (2.8 km) Jindalee OTH radar uniform linear array located near Alice Springs in central Australia.